Gc (vitamin D-binding protein) binds the 33.5 K tryptic fragment of actin

Life Sci. 1986 Feb 24;38(8):735-42. doi: 10.1016/0024-3205(86)90588-6.


Limited proteolysis of G-actin was performed with trypsin and chymotrypsin to compare the binding sites for Gc and DNase. DNase I bound to the N-terminal area corresponding to the major cleavage site on G-actin (residues 62-68) and inhibited proteolysis, but did not bind the 33.5K C-terminal fragment (G-actin33.5) generated. In contrast, Gc did not exert any inhibitory effect upon proteolysis of the intact native G-actin42.0 molecule, although its presence protected G-actin33.5 from further proteolysis. This was shown by gel filtration to be due to the formation of complexes between Gc and G-actin33.5.

MeSH terms

  • Actins / metabolism*
  • Binding Sites
  • Chymotrypsin / metabolism
  • Deoxyribonucleases / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Peptide Fragments / metabolism*
  • Trypsin / metabolism
  • Vitamin D-Binding Protein / metabolism*


  • Actins
  • Peptide Fragments
  • Vitamin D-Binding Protein
  • Deoxyribonucleases
  • Chymotrypsin
  • Trypsin